Structure for indicating need for removing suction cleaner dust bag



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June 19, 1956 E. R. CARLBERG STRUCTURE FOR INDICATING NEED Foa REMovING Filed Dec. 11. 1953 SUCTION CLEANER DUST BAG /JA lill. ...4. u l

nited States Patent O STRUCTURE FOR lNDICATlNG NEED FOR RE- MOVING SUCTION CLEANER DUST BAG Erik Reinhold Carlberg, Stockholm, Sweden, assignor to Aktiebolaget Elektrolux, Stockholm, Sweden, a corpou ration of Sweden Application December 11, 1953, Serial No. 397,743

Claims priority, application Sweden December 20, 1952 8 Claims. (Cl. 116-65) My invention relates to suction cleaners of the type which employ a removable dust bag or filter element, and it is an object of the invention to provide an improvement for automatically indicating when such a dust bag should be removed to be cleaned or replaced by a fresh dust bag.

More particularly, it is an object to provide such an indicator which is audible and can be readily heard by anyone in the vicinity of the cleaner, so that the dust bag can be cleaned or replaced immediately by a fresh dust bag when the need for doing so arises. I accomplish this by providing a device, which automatically becomes operable responsive to a predetermined pressure diierential at opposite sides of the dust bag due to dust and debris trapped therein, for producing an audible sound.

The above and other objects and advantages of my invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specilication.

For a better understanding of my invention, reference may be had to the following description taken in connection with the accompanying drawing in which:

Figs. 1 and 2 are fragmentary vertical sectional views of a vacuum cleaner embodying my invention; and

Fig. 3 is a side View, partly in section, of a vacuum cleaner to illustrate more clearly the manner in which the details of Figs. 1 and 2 may be incorporated in the cleaner.

Referring to Fig. 3, the suction cleaner which I have shown embodying my invention comprises a casing having a front end cover 11 and a rear hood 12 removably secured thereto in any suitable manner. The casing 10 is provided with a handle 14 and also suitable runners 15 to facilitate movement thereof on a supporting surface. A space 16, which is located at the end of the casing 10 at the vicinity of the front end cover 11, is adapted to receive a dust collecting member 17. The dust collecting member 17 comprises a filter bag 18 which may be formed of fabric or other suitable material permeable to air, and a part 19 of annular form which is fixed to the bag at the open end thereof. As best shown in Figs. 1 and 2, the part 19, which is essentially ring-shaped and serves as a reenforcement, is formed with an outwardly extending flange to which is fixed a gasket 20 which is formed of a resilient material like rubber, for example.

The casing 10 is provided with an end ring 21 having an inwardly extending flange 22 Which defines the access opening 23 into the space 16. The front end cover 11 is provided Afor the casing 10 to close the access opening 23 of the space 16 and also effectively hold the gasket 20 between the liange 22 and the cover. As shown, the cover 11 includes an inner apertured plate 24 which is fixed at its outer peripheral edge at in a notched or recessed portion of the cover, the plate 24 being arranged to act and bear against the gasket 20 of the dust collecting member 17.

The cover 11 is formed with a central opening which Patented June 19, 1956 ICC receives a hollow tubular member 26 at the inner end of which the apertured portion of the plate 24 is located. A suction hose (not shown) is adapted to be removably secured to the hollow tubular member 26 in any suitable manner. Suitable cleaning appliances may be connected to a wand which in turn is connected to the outer free end of the suction hose and through which air is drawn into the interior of the casing 10 by a motor fan unit (not shown) which may be positioned adjacent the filter bag 18.

During operation of the suction cleaner, air is drawn into the interior of the casing 10 through the hollow tubular member 26 in the front end cover 11. Dust and dirt entrained in the air during a cleaning operation collect in the lilter bag 18, and air free of such dust and dirt passes through the ilter bag and flows through the casing and is eventually discharged by the motor fan unit through an end opening in the rear hood 12. Since foreign matter is trapped at the inner surface of the filter bag 18, there is a tendency'for the iilter bag to become clogged during operation of the cleaner, the pressure differential at opposite sides of the iilter bag becoming'increasingly greater responsive to debris and dust trapped at the inner side of the bag which is initially contacted by the dust laden zur.

In accordance with my invention, in order to indicate when the filter bag 18 should be cleaned or replaced by a fresh lter bag, I provide a device 27, which automatically becomes operable responsive to av predetermined pressure differential at opposite sides of the filter bag due to dust and debris trapped therein, for producing an audible sound. The sound producing device 27 is associated with the cover 11 and forms a unitary part thereof. As best shown in Figs. 1 and 2, the cover 11 is formed with a cavity or recess 28 having an opening 29 to the atmosphere. The cavity or recess 28 defines a chamber which is closed by a plate or disc 30, the peripheral edge portion of which is secured tightly in any suitable manner to the cover at the enlarged end of the recess. The plate 30 is formed with a central passage or opening 31 which serves as a seat for a diaphragm 32, the peripheral edge portion of which is held between a circular-shaped raised seat 33 on the cover 11 and the enlarged end of a cup-shaped housing 34.

lThe diaphragm 32 is movable toward and from the opening 31 and biased against the plate 30 to close such opening by a helical spring 35, the latter being positioned about a hollow tubular sleeve 36 in the housing 34 within which a pin 37, which is anchored to the diaphragm, is guided. A passage 38 is formed in the cover 11 so that the space 39 formed between the plate 30 and diaphragm 32, when the latter closes the opening or passage 31, is substantially at the same pressure as the pressure within the filter bag 18. As best shown in Fig. 3, the passage 38 is formed at the vicinity of the inside wall of the cover 11 and extends radially outward from the inner apertured portion of plate 24 to the region of the circular-shaped raised seat 33. During operation of the cleaner when air is drawn into the inlet at 26, the pressure in chamber 39, at one side of the diaphragm 32, will be the same as the pressure existing within the filter bag 18 at the side thereof which is initially contacted by the air.

As shown in Figs. 1 and 2, a hollow sleeve 40, which extends through an opening in the inner plate 24 of cover 11 and communicates with an opening 41 in the flange 22 of end ring 21 of the casing, provides a passage so that the space 42 at the opposite side of the diaphragm 32 is substantially at the same pressure as the pressure in space 16 at the outer surface of the filter bag 18. The sleeve 40 desirably is formed of a suitable resilient material, such as rubber, for example, and formed with an enlarged head 43 and a pair of sealing rings or flanges 44 and 45, respectively. The head 43 and sealing ring 44 cooperate to anchor the sleeve 4i) within an aperture or opening in the base of the cup-shaped member 34, the sealing ring 44 also being arranged to act against the inner cover plate Z4 to provide a good seal about the opening therein through which the sleeve passes. The sealing ring 45 is more or less funnel-shaped and acts resiliently against the flange 22 and covers the opening 41 therein when the cover 11 is mounted on the casing.

During operation of the cleaner', dust laden air is drawn into the casing llt) through the central opening in the cover 11. Dust and other foreign matter are trapped in the filter bag 38, and air free of such foreign matter passes through the filter bag. When the filter bag i3 is clean, the pressure differential at opposite sides of the bag is relatively small. Under these conditions, the pressure in chamber 42, aided by the biasing action of the spring 35, will he effective to maintain the diaphragm 32 seated against the plate 30, so that air in the space 39 cannot pass into opening 31. However, when the filter bag 13 becomes clogged, due to dust and debris collected therein, and the pressure differential at opposite sides of the bag reaches a predetermined value, the pressure in chamber 42 will be reduced sufficiently to allow the diaphragm 32 to move from the plate 30.

Accordingly, when the pressure in chamber 42 decreases to such an extent that the pressure in space 39 will be effective to operi passage 3l against the biasing action of the spring 35, air drawn into the casing 10 can flow at a relatively high velocity through passage 38, space 39 and passage 3l into the cavity 28 and pass therefrom to the atmosphere through opening 29 in the cover 11. One or both of the openings 29 and 31 may be of such crosssectional area that, when air flows therethrough at a relatively liigh rate of speed, a whistling sound will be produced. When such an audible sound is produced, anyone in the vicinity of the cleaner will immediately know the dust collecting member 17 should be withdrawn from the casing )i0 for cleaning the latter or providing a fresh filter bag -in the event paper bags of the throw away type are employed.

Although I have shown and described a single embodiment of my invention, I do not wish to be limited to the particular arrangement set forth, and I intend in the following claims to cover all modifications which do not depart from the spirit and scope of my invention.

What is claimed is:

l. In a suction cleaner having a casing provided with an inlet and outlet for air adapted to flow therethrough and a filter element therein for removing foreign matter from air, the pressure differential at opposite sides of said filter element becoming increasingly greater responsive to foreign matter trapped at the side thereof initially coritacted by the air, a device for producing an audible sound with the aid of air, movable valve means to control flow of air for operating said device, and means responsive to a predetermined pressure differential at opposite sides of said filter element to actuate said valve means for effecting iiow of air to operate said device and produce such an audible sound.

2. In a suction cleaner having a casing provided with an inlet and outlet for air adapted to flow therethrough and a filter element therein for removing foreign matter from air, the pressure differential at opposite sides of said filter element becoming increasingly greater responsive to foreign matter trapped at the side thereof initially contacted by the air, a device for producing an audible sound with the aid of air flowing through said casing, valve means i carried by said casing to control flow of air for operating said device, and means responsive to a predetermined pressure differential at opposite sides of said filter element to actuate said valve means to divert a part of the air liowing through said casing and effect the liow of diverted air to operate said device and produce such an audible sound.

3. In a suction cleaner having a casing provided with an inlet and outlet for air adapted to ow therethrough and a filter element therein for removing foreign matter from air, the pressure differential at opposite sides of said filter element becoming increasingly greater responsive to foreign matter trapped at the side thereof initially coritacted by the air, a device having a passage communicating with the atmosphere for producing an audible sound with the aid of air flowing therethrough, and means responsive to a predetermined pressure differential at opposite sides of said filter element to establish a path of flow for air Within said casing from one side of the filter element to the passage of said device and from the latter exteriorly of said casing to the atmosphere to produce such an audible sound.

4, ln a suction cleaner having a casing provided with an inlet and outlet for air adapted to flow therethrough and a ilter element therein for removing foreign matter from air, the pressure differential at opposite sides of said filter element becoming increasingly greater responsive to foreign matter trapped at the side thereof initially contacted by the air, a device having an opening for producing an audible sound with the aid of air liowing therethrough, means including a valve member for closing the opening for substantially preventing flow of air through said device, a movable diaphragm disposed within said casing, and means including said diaphragm which is responsive to a predetermined pressure differential at opposite sides of said filter element for moving said valve member from the opening to cause air to ow through said device to produce Stich an audible sound.

5. Apparatus as set forth in claim 4 including resilient means to bias said diaphragm in one direction for moving said valve member to close the opening, said diaphragm being movable in the opposite direction against said biasing action responsive to the predetermined pressure differential at opposite sides of said filter element for moving said valve member from the opening to cause air to flow through said device.

6. Apparatus as set forth in claim 4 including a partition within said casing, means defining a first space in said casing at one side of said partition into which air passes through said filter element, means including said diaphragm defining a second space at the opposite side of said partition, said partition having an aperture, and means including a hollow sleeve communicating with said aperture to establish communication between said first space and said second space at one side of said diaphragm.

7. In a suction cleaner having a casing provided with an inlet and outlet for air adapted to flow therethrough and a filter element therein for removing foreign matter from air, the pressure differential at opposite sides of said filter element becoming increasingly greater responsive to foreign matter trapped at the side thereof initially contacted by the air, a device for producing an audible sound responsive to air flowing into said casing through said inlet, movable valve means within said casing for controlling said device, and means responsive to a predetermined pressure differential at opposite sides of said filter element for regulating said valve means to cause air flowing into said casing through said inlet to operate said device to produce such an audible sound.

8. In a suction cleaner having a casing provided with an inlet and outlet for air adapted to .flow therethrough and a filter clement therein for removing foreign matter from air, the pressure differential at opposite sides of said filter element becoming increasingly greater responsive to foreign matter trapped at the side thereof initially contacted by the air, a device having a passage to establish communication with the interior of said casing and the atmosphere for producing an audible sound with the aid of air iiowing therethrough to the atmosphere, movable valve means within said casing comprising a diaphragm 5 6 movable between a rst position to close said passage and References Cited in the le of this patent a se cond position to open said passage, and means .for UNITED STATES PATENTS movmg sald diaphragm from its first to 1ts second position 2 523 967 N l i responsive to a predetermined pressure differential at oppo- 2682250 Sept 26 1950 site sides of said lter element to divert a part of the air 5 ne June 29 1954 flowing into said casing through said inlet and cause the diverted air to ow through said passage to the atmosphere to produce an audible sound. 

